Electrical power and control mechanism for electrical appliances



Aug. 10, 1965 R, J. ToLMlE ELECTRICAL POwER AND CONTROL MECHANISM FORELECTRICAL APPLIANCES Filed Jan. 29, 1962 176.2 N H gli INVENTOR.Raaf/e7' f 700w/E United States Patent O 3,200,319 ELECTRICAL PWER ANDCONTROL MECHs ANISM FOR ELECTRICAL APPLIANCES Robert J. Tolrnie,Fairfield, Conn., assigner to Sperry Rand Corporation, New York, N.Y., acorporation of Delaware Filed Ilan. 29, 1962, Ser. No. 169,685 Claims.(Cl. 320-2) The invention relates to electrical power and control-mechanisms for electrical appliances and especially to such mechanismsfor portable appliances of relatively small size, weight and capacityadapted for low voltage actuation selectively from either aself-contained replenishable direct power `source forming part of theappliance or from an external power source.

Portable appliances, such as electric dry shaver apparatus, having adriving motor, a switch and a battery mounted in a shaver container forportable use, are already well known in the art. It is desirable toequip such portable appliances with a rechargeable battery and electriccircuit which permit the driving motor to be selectively energized fromeither the battery or an external power source while permitting periodicrecharging of the battery, while mounted, in its operating position.

It is, therefore, an object of this invention to provide for suchelectrical appliances of the portable type, improved electrical powerand control mechanism permitting selective energization of the appliancefrom either a rechargeable battery incorporated in the appliance or anexternal source of power and, alternately, recharging of the batteryfrom such external power source.

Another object is to provide such an electrical power and controlmechanism which is of simple, economical design and utilizes presentlyavailable standrd circuit components.

A further Objectis to provide such an electrical power andcontrolmechanism which maximizes safety to the equipment and to the user of theappliance, notwithstanding that the appliance may be misused.

It is still a further object of the invention to provide electricalpower and control mechanism for such portable appliances havingdiffering operating characteristics.

it is yet another object of the invention to provide electrical powerand control mechanism for such portable appliances for selectivelyconnecting the driving motor of vsuch an appliance for energization to arechargable battery forming part of the appliance, or to an externalsource of power, and alternately the rechargeable battery to theexternal source for recharging operation, while effectively electricallyisolating the motor and battery one from the other.

The invention involves providing in an electrical appliance anelectrical device, which may be termed a power pack, adapted, whenconnected to a source of alternating power, for providing unidirectionalpower at a certain magnitude, and means for selectively connectingeither the driving motor of the appliance or its rechargeable battery tothe output of such power pack, while effectively electrically isolatingone from the other, and, alternately, for connecting the driving motorto the battery for energization therefrom.

In carrying out the invention, according to a preferred embodiment,electrical circuit means are provided for automatically limiting, underconditions where the bat- YICC tery is selectively7 connected to thepower pack for recharging, the magnitude of the unidirectional powerapplied by the power pack to the battery to a value which permits thebattery to be left on charge substantially indefinitely, without damageto the battery or power pack.

Features and advantages of the invention will be seen from the above andfrom the following description of operation when considered inconjunction with the drawings and from the appended claims.

In the drawings:

FIGURE l is a simplified schematic wiring diagram of an electrical powerand control mechanism for an electric motor driven appliance having aself-contained rechargeable unidirectional power source and a power packfor converting alternating power from an external power source tounidirectional power;

FIGURE 2 is a simplified schematic wiring diagram of a modifiedembodiment of the electrical power and control mechanism of FIGURE l;

FIGURE 3 is a Isimplified schematic wiring diagram of an electricalpower and control mechanism similar to the embodiment of FIGURE 1 bututilizing a three conductor current conduit between the appliancedriving motor, its self-contained unidirectional power source and theirassociated power pack;

FIGURE 4 is a simplied schematic wiring diagram of a slightly modifiedembodiment of the electrical power and control mechanism of FIGURE 3;

FIGURE 5 is still another simpliied schematic wiring diagram of amodified embodiment of the electrical lpower and control mechanism ofFIGURE 1 but utilizing a three prong male plug and cooperating two holefemale receptacle for selectively connecting either the appliancedriving motor or its self-contained unidirectional power source to apower pack; and

FIGURE 6 is yet another simplified schematic wiring iagram of a moditiedembodiment of the electrical power and control mechanism of FIGURE 3.

For convenience, the subject invention will be described as applied toan electric dry shaving apparatus selectively operable from either aself-contained, rechargeable battery or an external alternating powersource, it being understood, nevertheless, that the invention is not solimited and without departing from the spirit and yscope thereof isapplicable to similar electrical appliances.

Referring to FIG. l wherein a preferred embodiment of the subjectinvention is illustrated, TR designates a transformer, having a primarywinding TRP and a secondary winding TRS; primary winding TRP beingadapted for connection to a source of alternating power (not shown),such as, for example, as is available from a standard householdalternating power outlet. Transformer secondary winding TRS is connectedat its ends and through a midtap to a full wave rectifier RE forconverting the alternating power to unidirectional power at a voltage ofrelatively low and harmless magnitude. The i rectified output is appliedto terminals i3, 14 for application over conductors lil and ll to theshaver apparatus.

Preferably, transformer TR and rectifier RE, termed power pack PP, areenclosed in a container separate from that of the shaver apparatus,generally designated SA, to which power pack the shaver apparatus SA maybe electrically connected at `terminals i3, 14 by means of a male plugand a female receptacle assembly, which is of tor. .selectivelyconnecting motor rotor MR either directly fswitch RSfor switch KS ofFIGURE 1.

Yconsists of a rotary brush BRS and four segmental stathenon-symmetrical type to insure that power is applied to the shaverapparatus SA at the proper polarity; the male plug with a flexible twoconductor power cord being integrally attached to shaver apparatus SAand the coacting female receptacle being mounted on the power packcontainer.

MR designates the rotor of a direct current driving motor of shaverapparatus SA and PMF designates its permanent magnet field. B designatesa rechargeable relatively low voltage battery for energizing the shaverdriving mo- KS designates a three position manual switch for acrossconductors and 11 or directly across battery B Vfor energization in apredetermined direction of rota'- -tion, or for disconnecting the motor.R deslgnates a current limiting and isolating resistor of predeterminedohmic value, permanently connecting the positive terminal of battery Bto conductor 10, for purposes to be explained hereinafter. y

Assume that it is desired to operate shaver apparatus SA from battery B.To accomplish this, shaver apparatus SA is preferably disconnected fromits associated power pack PP at terminals 13, 14, and manual switch AKSis then moved to its position I, connecting motor rotor MR directlyacross battery B for energization for a certain direction of rotation.

yNext asume that it is desired to operate shaver apparatus SA from anexternal alternating power source. Undersuch conditions, shaverapparatus SA is plugged into power pack PP at terminals 13, 14 and powerpack PP is, in turn, plugged into an alternating power outlet. Switch KSis then moved to its position III, connecting motor rotor MR directlyacross the output ofvrectifier RE for energization for a predetermineddirection of rotation from the external power source. With 'switch KS inposition III, motor rotorMR is also connected in parallel with thebranch circuit consisting of resistor R in series with battery B.Depending upon the magnitude of the load placed on the shaver drivingmotor, current flows in the branch circuit in either a battery chargingor discharging direction. However, resistor R is selected of such ohmicvalue as to limit the current fiow in the branch circuit tosubstantially a negligible and insignificant amount, effectivelyelectrically isolating battery B from the rectified output of rectifierRE and motor rotor MR.

Next assume that it is desired to recharge battery B from the externalalternating power source. To accomplish this, manual switch KS is movedto its normally .open position II, thereby disconnecting motor rotor MRvfrom both the output of rectifier RE and from battery B; resistor R nowacting as a current limiting resistor in series with battery B to limiteffectively the charging of battery B to a predetermined safe rate suchthat the battery may be left substantially indefinitely on chargeWithout damage to the equipment.

Next assume that while shaver apparatus SA is con-v nected to power packPP manualswitch KS is moved inadvertently to position I, connectingmotor rotor MR directly across battery B and through resistor R to theoutput of rectifier RE. Resistor R is of such ohmic value as tolimitunder such circumstances, power applied to motor rotor MR frompower pack PP to an amount insufficient to effect driven movement of themotor rotor from'the external power source. `Motor Vrotor MR is insteadenergized by battery B sufficiently for proper operation of the shaver.Y f

InFIGURE 2 is illustrated'an electrical power and control mechanismsimilar to that of FIGURE 1 but slightly modified by substituting'amanual rotary-type Switch RS tionary contacts RSI-4; brush BRS beingadapted for selectively electrically interconnecting selected ones ofstationary contacts RSI-4 to each other. For example,

Yfrom the external alternating power source.

4 with rotary brush BRS in position I, as shown, stationary contacts RSSand RSI are electrically connected to each other, causing the output ofrectifier RE to be applied directly to motor rotor MR for energizationof the shaver motor for rotation in a predetermined direction from theexternal alternating power source.

Next assume that brush BRS of switch RS is moved to its position Il,disconnecting contacts R81 and RSS and connecting stationary contactsRSI and RS4 electrically to each other, thereby placing motor rotor MRdirectly across battery B for energization therefrom for rotation of theshaver rotor in the aforementioned predetermined direction.

Next assume thatrit is desired to recharge battery B To accomplish this,brush BRS is Vmoved to its position III, electrically connecting itsstationary contacts RSZ and RS4 to each other, thereby connectingbattery B through resistor R to the output of rectifier RE; resistor Rbeing selected of such ohmic value as to limit the charging currentapplied to battery B to a safe rate, at which charg ing rate the batterymay be left on charge substan tially indefinitely without being damaged.

It may be noted that with the arrangement of FIG- URE 2, underconditions where it is desired to operate the shaver from bat-tery B,i.c. when brush BRS is in position II, motor rotor MR and battery B areboth electrically disconnected from power pack PP and directly connectedto each other. It may be seen that motor rotor MR and battery B are thuselectrically connected to each other only under conditions where brushBRS is in position II for operating the shaver from battery B, and,under conditions where brush BRS is rotated to either 'of its other twoportions (I or Il), motor rotor MR and battery B are electricallydisconnected from each other, thereby obviating the .undesirableconnection of vboth simultaneously to the output of rectifier RE.

Shown in FIGURES 3 through 4 ofthe drawings are electrical power and'control mechanism embodiments particularly suitable to dry shavingapparatus, or electrical appliances, which require power of a greatermagvd nitude than is required by the dry shaving apparatus to which theembodiments shown in the circuitry of FIG- URES 1 and 2 are applicable.For such shaving apparatus which requires a greater amount of power, itis desirable to provide power and control mechanism which, underconditionsV where the shaver driving motor is opd erated from anexternal alternating source, provides the kdesired greater amount ofunidirectional power, and, under conditions where battery B of theshaver apparatus is to be recharged from such external alternatingsource, automatically reduces the magnitude of the unidirectionalcharging power applied to the battery to a value which provides acharging rate which permits the battery to be left on charge7substantially indefinitely without being damaged. It is also desirableto utilize, in such power and control mechanisms, a power pack ofrelatively small size and weight, of simple and economical constructionand yet prevent damage thereto by excessive heating. Y

Referring to FIGURE 3, al power pack PP similar to that shown in thecircuitry FIGURES 1 and 2 for connection to an alternating power source(not shown) is provided with the exception that a resistor RA ofpredetermined ohmic value is connected in series with primary windingTRP of transformer TR, and the junction point P of resistor RA andprimary winding TRP is connected directly to a midtap on transformersecondary winding TRS. The other sideY of resistor RA is connecteddirectly to an output terminal 15 of power pack PP; the latterpreferably being provided with a nonsymmetrical female receptacle foraccommodating a corresponding three prong male plug at 13, 14 and 15attached by means of a flexible three conductor 10,: 1.1 17Y power cordto shaver apparatus SA..

Positive terminal -lof battery B is connected directly to conductor andto one brush of rotor MR of the driving motor. Its negative terminal isdirectly connected to one stationary contact of a three position manualswitch KS and through a current limiting and isolating resistor RB ofpredetermined ohmic value to the other stationary contact of switch KSand to conductor 11. The other brush of motor rotor MR is connected tothe movable contact of switch KS and to conductor 17.

With switch KS in its normally open position II and the shaver apparatusconnected to power pack PP at terminals 13, 14, 15, as shown,unidirectional power at a predetermined magnitude is applied from powerpack PP to battery B to effect charging of the battery at apredetermined rate; the charging circuit extending through currentlimiting resistor RB. Resistor RB in the battery charging circuit andresistor RA in the circuit of primary winding TRP (where it acts tolimit current through the winding and, in turn, the rectified output ofrectifier RE) are selectedr of such ohmic value as to effectively limitthe charging of battery B to a predetermined safe rate, whereby it maybe safely left on charge substantially indefinitely. Resistor RA is alsoselected of such ohmic value as to limit the current flow in primarywinding TRP to an amount which obviates excessive heating of transformerTR.

With switch KS in battery charging position II, opening the motorVcircuit, resistor RA is also connected in a parallel circuit whichextends from positive terminal of battery B through motor rotor MR overconductor 17 to terminal 15 and through resistor RA to the midtap ofsecondary winding TRS. Resistor RA is of such ohmic value as to insertsufficient resistive impedance in series with motor rotor MR as toreduce eli'ectively energization of the rotor MR, when in such parallelcircuit, to a negligible amount.

Nexty assume that it is desired to operate the shaver driving motor ofFIGURE 3 from the external alternating source through power pack PP.Under such conditions, switch KS is moved to its position III,connecting motor rotor MR directly across the output of rectifier RE forenergization for a predetermined direction of rotation from the externalpower source. At the same time, resistor RB is automatically connectedin series with battery B in a branch circuit in parallel with motorrotor MR. Resistor RB is of such ohmic value as to limit current flow insuch branch circuit to a negligible amount, thereby in effectelectrically isolating battery B and motor rotor MR from each other.

Movement of switch KS to position III also completes a low resistanceshunt path (short circuit path) around resistor RA in the circuit ofprimary winding TRP of transformer TR, thereby increasing current flowthrough the primary winding, energization of the transformer and, inturn, the rectiiied output of power pack PP to a predetermined motoroperate value for driving the shaver motor; the shunt circuit extendingfrom junction point P through terminal 14, conductor 11, switch KS inposition III, conductor 17, terminal and resistor RA back to junctionpoint P.

` Next assume that it is desired to operate shaving apparatus SA ofFIGURE 3 by means of its self-contained battery B. Under suchconditions, power pack PP is unplugged from the alternating power outlet(not shown) and/or shaver apparatus SA is unplugged from power pack PP.

It may be noted that, under conditions where shaver apparatus SA isunplugged from power pack PP and the Y power pack remains connected tothe external alternating source, resistor RA is Vautomaticallyreinserted in the circuit of transformer primary winding TRP, reducingthe current liow therein to a magnitude which enables power pack PP tobe left connected under no load conditions without damage fromoverheating. In addition, resistor RA effectively minimizes transientcurrents induced in primary winding TRP by the collapse of the magneticiield of secondary winding TRS incident to shaver apparatus SA beingunplugged from power pack PP.

Next, switch KS is moved to its position I, connecting motor rotor MRdirectly across battery B for energization therefrom for rotation in apredetermined direction.

It may be noted that, when switch KS is moved to its position I foroperation of the shaver driving motor from battery B, should shaverapparatus SA inadvertently remain plugged into power pack PP and thepower pack remain connected to an external alternating source, resistorRA is automatically reinserted in the primary winding circuit oftransformer TRP, reducing the rectified output of power pack PP to apredetermined safe amount, and resistor RB is inserted in series withthe presently parallel connected battery B and motor rotor MR, therebyeffectively reducing the current applied thereto by power pack PP tol anegligible amount.

In recapitulation, it may be noted that with the arrangement of FIGURE3, under conditions where switch KS is in its position III, resistor RAis short circuited, increasing the excitation of transformer TR and therectitied output applied by power pack PP to the motor rotor MR toprovide suiiicient energization of the driving motor. Under conditionswhere it is desired to recharge battery B, switch KS is moved to itsposition II, disconnecting motor rotor MR from conductor 11 andreinserting resistor RA in the primary winding circuit of transformer TRand resistor RB in the battery charging circuit, thereby reducing therectified output applied to the battery to a predetermind safe amountwhich allows the battery to be left on charge substantially indefinitelywithout overheating power pack PP. When it is desired to operate theshaver driving motor by means of battery B, switch KS is moved toposition I, connecting motor rotor MR directly across battery B forenergization therefrom. Should switch KS be moved to position I forbattery operation of the shaver, while shaver apparatus SA is connectedto the output of power pack PP, resistor RA is connected in thetransformer primary winding circuit and resistor RB is connected inseries with both battery B and motor rotor MR to eiectively limitcurrent iiow from power pack PP to shaver apparatus SA to a negligibleamount which does not interfere with battery operation of the shaver.

In FIGURE 4 the circuitry of FIGURE 3 has been slightly modified bysubstituting a rotary switch RS for the three position manual switch KSof FIGURE 3 to allow battery B to be electrically connected to motorrotor MR only under conditions where it is desired to operate the shaverdriving motor from the battery. Rotary switch RS consists of a manuallymovable rotary brush BRS and five segmental stationary contacts RSI-5;the switch being arranged such that movement of rotary brush BRS intoposition I electrically interconnects its stationary contacts RSI, 3 and5 to each other, movement of brush BRS to position Il electricallyinterconnects its stationary contacts RSI and 4 and movement of brushBRS to position III electrically interconnects its stationary contactsRSZ and 4.

Assume that it is desired to operate the shaver driving motor directlyfrom an external source of alternating power. Under such conditions,lshaver apparatus SA is connected to power pack PP which, in turn, isconnected to an alternating source of power (not shown). Rotary brushBRS is then moved to its position I, as shown, thereby interconnectingits stationary contacts RSI, 3 and 5 together. In such position, rotarybrush BRS connects motor rotor MR directly across the output ofrectiiier RE via stationary contacts RSI, 3 interconnected by brush BRSwhile short circuiting resistor RA in the circuit of transformer primarywinding TRP via stationary contacts RSS, 5 also interconnected by brushBRS to cause power pack PP to produce increased rectified power of apredetermined motor operate magnitude.

Next assume that it is desired to operate the shaver driving motordirectly from battery B. Under such conditions, brush BRS of rotaryswitch -RS is moved to its position II, disconnecting motor rotor MRfrom power pack PP and interconnecting its stationaryrcontacts RSI and4, thereby connecting motor rotor MR directly across battery B forenergization therefrom. Brush BRS in mov ing to its position II alsoslides off of its stationary contacts R83, 5, removing a short circuitfrom across resistor RA which is thus reinserted in the'primary windingcircuit of transformer TR, causing a reduction yin current liow inprimary winding TRP, thereby protecting the transformer fromoverheating. f `V Next assume that it is desired to charge battery Bfrom the external power source by means of power pack PP. Under suchconditions, brush BRS of rotary switch RS is moved to its position III,interconnecting its stationary contacts RSZ and RS4, thereby connectingbattery B through current limiting resistor RB to the output ofrectifier RE; the charging Vcircuit extending from terminal 13 throughconductor 10, battery B, stationary contacts RS4, 2 of switch RSpresently interconnected by brush BRS, current limiting resistor RB,stationary contact RS3 and conductor 11 to terminal 14 of power pack PP.Resistor RB in series with battery B in such charging circuitandresistor RA in the circuit of primary winding TRP of transformer TR actin conjunction to limit effectively the rectified power applied tobattery B to a predetermined safe amount, thereby limiting the chargingof battery B to a rateV which allows it to be left on chargesubstantially indefinitely without damage to the battery or the powerpack. y

It may be noted that in the embodiment of FIGURE 4, wherein resistor RBis utilized as a current limiting resistor during the charging ofbattery B, if it is desired, such resistor RB may be omitted from thecircuit and replaced by an electrical wire interconnecting stationarycontacts RSZ Vand RSS of switch RS. A safe charging rate for battery `Bmay then be obtained by selecting resistor RA in the circuit of primarywinding TRP of such increased ohmic value as to limit the output ofpower pack PP applied to battery B during charging operation to apredetermined amount to attain a safe charging rate, whereby the batterymay be left on charge substantially indefinitely. v

FIGURES 5 and 6 illustrate modified embodiments of the power and controlmechanisms of FIGURES 1 and 3, respectively, in that single pole,singlek throw, manual switches are utilized in lieu of lthe threeposition, manual switches KS of FIGURES l and 3. K

With reference to FIGURE 5, a power pack PP and shaver apparatus SA areillustrated. Shaver apparatus SA is equipped with a three conductor 10,11 and 17 power cord, terminating in a three prong male plug MP; theprongs being designated H1, G1 and H2. Power pack PP -is provided with atwo hole prong receiving outlet OT for applying unidirectional power toshaver apparatus SA; the loutlet holes being designated H and G. Plug MPand its cooperating power outlet OT are preferably of thenon-symmetrical type to insure that power is applied to shaver apparatusSA from power pack PP at the correct polarity; prong G1 of plug M-P andoutlet hole G being shaped for cooperation only with each other,whileeither of prongs H1 and H2 may be plugged into outlet hole I-I.Motor rotor -MR of the shaver driving motor is connected Y at oneV sideto prong H1 and through manual switch KSI,

which is normally open, t-o positive terminal of battery B. Positiveterminal -1- of battery B is connected through current limiting resistorvR to prong H2, while its negative terminal is connected directly `tothe other side of motor rotor MR and through normally closed manualswitch KSZ to Vprong G1. `Manual switches KSl, KS2,

are mechanically interlocked to each other and thereforel lare operatedin unison, as will be described hereinafter. Y

Assume that it is desired to operate the shaver'driving motor from itsself-contained battery B. Under such circumstances, `manual switch KSlis moved,l to its closed position, connecting motor rotor MR directlyacross batftery B for energization therefrom. It maybe noted that switchKS2, mechanically interlocked with switch KSI, is simultaneously opened.Thus, should shaver apparatus SA inadvertently be connected to theoutput of power pack PP by either of prong sets H1, G1 or H2, G1 ofshaver plug MP being plugged intoy power pack out-let OT, switch KS2,presently open for battery operation of the shaver driving motor,prevents completionv of a circuit from power pack PP to shaver apparatusSA, thereby preventing application of unidirectional power from thepower pack to either motor rotor MR or battery B and interference withbattery operation of the shaver.

Next .assume that it is desired to operate the shaver driving motor froman external power source. Under such circumstances, shaver apparatus SAis connected to power pack PP by means of prongs H1, G1 of plug MP beingplugged into power pack outlet OT. Manual switch KSl is moved to itsnormally open position, disconnecting motor rotor MR from Aacrossbattery B. Switch KS2 simultaneously moves to its lclosed position,connecting motor rotor MR to output of power pack PP for energizationfrom the external alternating source.

Next assume that it is desired to charge battery B from the external-alternating source. Under such circu-m# stances, shaver apparatus SA isplugged into power pack PP; prongs H2 and G1 of plug MP being pluggedinto power pack outlet OT to apply the rectied output of Y power pack PP.to battery B through current limiting resistor R andl switch KS2(presently closed). Resistor R is selected -of such ohmic valueras tolimit current iiow in the charging circuit of battery B to apredetermined safe r-ate which permits the battery to be left on chargesubstantially indefinitely without either battery B or power pack PPbeing damaged. s

The vembodiment of FIGURE 6 is utilized for Shavers which require agreater amount of power than those for which .the circuitry of FIGURE 5is used. A power pack PP capable of providing such greater power isillustrated, and is equipped with a power outlet, generally designatedOT, for-.accommodating a non-symmetrical corresponding male plug; theprong receiving holes of outlet OT being Vdesignated 13, 14 .and 1S.YShaver apparatus SA is equipped with a double male plug, generallydesignated MDP, consisting of tworsets of prongs; the prongs of one setbeing designated 13', 14' and 15 and those for the other set 13', 14 and'15, prong 13' being common to both sets; Either set of prongs may beplugged into power outlet OT for connecting power pack PP to shaverapparatus SA. Motor rotor MR is connected at one side to prong 14',which prong is internally short circuited t-o prong 15', and at theother side through normallyclosed, manual switch KS2 to prong 13 and topositive terminal 4# of battery B. Negative terminal of battery B isconnected toA prong 14", which, in turn, is connected through normallyopen, manual switch KS1 to prong 14. Manual switches KSI, KS2 aremechanical-ly interlocked one to the other, and therefore operate inunison. Prong 15 is a dummy.

Assume that it is desired to operate Ithe shaver driving motor directlyfrom its self-contained battery B. Under such circumstances, 4shaverapparatus SA is preferably disconnected from its 4associated power packPP, and switch KS1 moved to its closed position, connecting motor rotorMR directly across battery yB for energization therefrom. A

It may be noted that, if it is desired'to operate the shaver frombattery B, while shaver apparatus SA rem-ains connected to power pack PPby means of either set of the prongs of plug MDP, upon switch KSl beingmoved toV its closedrposition to place the shaver on battery operation,as has been described, switch KS2, mechanically 9 interlockedwith'switch KSI, is simultaneously moved to its open position,preventing the rectiiied output of power pack PP from being applied toeither motor rotor MR or battery B. Thus, notwithstanding that shaverapparatus SA is plugged into power pack PP, the shaver may be operatedfrom its self-contained battery B.

Next assume that it is desired to operate the shaver driving motor froman external source of alternating power. Under such circumstances,manual switch KS1 is opened, switch KS2 closed yand shaver apparatus SAis plugged into outlet OT of power pack PP by means of prong set 13', 14and 15 of shaver plug MDP. Shorted prongs 14', 15 of plug MDP place ashort circuit connection 'across resistor RA, increasing the ilow ofcurrent through primary winding TRP of transformer TR, and, in turn, therectified output of power pack PP to a predetermined motor operatemagnitude. Such output is app-lied directly across motor rotor MR; thecircuit extending from prong 13 (presently in outlet hole 13) throughmanual switch KS2 (presently closed) -and motor rotor MR to prong 14(presently in outlet hole 14); switch KSl, mechanically interlocked withswitch KS2, being maintained in its open position, thereby maintainingbattery B disconnected from the output of power pack PP.

Next assume that it is desired to charge battery B from an externalalternating source of power. Under such circumstances, shaver apparatusSA is plugged into power pack PP by means of its prong set 13', 14 and15", establishing Ia circuit for charging battery B from power pack PP;the charging circuit extending from prong 13' (presently in outlet hole13) through switch KS2 (presently closed) to the positive terminal ofbattery B, through battery B and from its negative terminal to prong 14(presently in outlet hole 14); switch KSl (presently open) maintainingmotor rotor MR disconnected trom power pack PP. With shaver apparatus SAthus connected to power pack PP, resistor RA is reinserted in thecircuit of primary Winding TRP of transformer TR, reducing the currentflow therein and, in turn, the rectitied output of power pack PP topredetermined magnitudes. Resistor RA is selected of such ohmic value asto provide a predetermined safe charging rate for battery B, at whichrate the battery may be left on charge substantially indefinitelywithout danger of damage to either the battery by overcharging, or tothe power pack by overheating.

In View of the foregoing description of the embodiments of FIGURES lthrough 6 of the drawings, it is seen that the subject inventionprovides electrical power and control mechanism for relatively smallportable appliances having their own self-contained replenishable,unidirectional power sources, which mechanism enables the appliance tobe selectively operated from either its selfcontained power source or analternating power source external thereto and, alternately,replenishment of the self-contained power source from the external powersource. The power -and control mechanism arrangement is such that thepossibility of damage occurring to the electrical components of theappliance through misuse is minimized, thereby permitting electricalcomponents of standard design and of relatively small size and weight tobe utilized therein.

As many changes could be made in the labove construction vand manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown on the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Electric-al power and control mechanism for an electrical appliancecomprising; a driving motor; a rechargeable battery; -a power packhaving two input terminals and a positive end and a negative outputterminal, said power pack being adapted when connected by its inputterminals to an alternating source of power for providing at said outputterminals unidirectional power at a certain magnitude for energizingsaid motor; and electric circuit connecting means including a currentlimiting resistor, said means being selectively operable to a firstcertain condition connecting said driving motor to said battery forenergization therefrom for rotation in a predetermined direction, and toa second certain condition connecting said battery to said outputterminals through said resistor for charging of said battery, saidresistor being of a certain ohmic value for limiting the magnitude ofsaid unidirectional power charging said battery to less than saidcertain magnitude for charging of said battery at a predetermined rate,said electric circuit connecting means also being operable to a thirdcertain condition connecting said driving motor to said outputtermin-als of said power pack for energization at said certain magnitudeof said unidirectional power for rotation in said predetermineddirection, and connecting said resistor in circuit with said batteryelectrically isolating said battery from said motor.

2. Mechanism as set forth in claim 1 wherein said electric circuitconnecting means includes a single pole, double throw manual switchhaving a normally open midposition and two closed positions, saidconnecting means being operable to said second certain condition whensaid connecting means being operable to said third certain conditionwhen said manual switch is in a first one of said two closed positions,thereby connecting said resistor and battery in series one with theother and in parallel with said motor, and said connecting means beingoperable to said rst certain condition when said manual switch is in theother of its closed positions, thereby connecting said resistor inseries with said parallel connected motor and battery.

3. Mechanism yas set forth in claim 1 wherein electric circuitconnecting means include a manual switch having two stationary contactsand a movable contact arranged for selectively engaging said stationarycontacts from a normally non-engaging position, said resistor ofpredetermined ohmic value resistively connecting said stationarycontacts one to the other, circuit wiring connecting one terminal ofsaid motor to said movable Contact, the other of said motor terminals tosaid negative output terminal of said power pack, said positive outputterminal of said power pack to a ltirst one of said stationary contacts,and said battery from the other of said stationary contacts to saidother of said motor terminals.

4. Electrical power and control mechanism for an electrical appliancecomprising; a driving motor having two motor terminals; a rechargeablebattery having a positive and a negative terminal; a power packconsisting of transformer means having a secondary and a primarywinding, a resistor of predetermined ohmic value connected in serieswith said primary winding, said secondary winding being connected at itsmidpoint to the junction point of said resistor and said primarywinding, and full wave rectitfying means connected to said seconda-rywinding for providing unidirectional power at a predetermined magnitudeunder conditions where said primary winding is connected through saidresistor to an alternating source of power; and electric circuitconnecting means selectively operable to a first certain conditionconnecting said driving motor across said battery for energizationtherefrom for rotation in a predetermined direction, to a second certaincondition Connecting said battery to said power pack for charging ofsaid battery, said electric circuit connecting means also being operableto a third certain condition connecting said driving motor to said powerpack, shorting said resistor in said primary winding circuit forenergizing said driving motor at a predetermined increased magnitude ofunidirectional power for rotation in said predetermined direction, and

11` connecting said battery for electrically isolating said battery fromsaid motor.

5. Mechanismv as set forth in claim 4 wherein said electric connectingmeans, includes a manual switch having two stationary contacts and onemovable contact arranged tfor selectively engaging said stationarycontacts from a normally non-engaging position, a second resistor ofpredetermined ohmic value resistively connecting said stationarycontacts one to the other, and circuit wiring connecting a first one ofsaid stationary contacts to said junction point of said primarycircuitresistor, the other of said stationary contacts to said negativeterminal of References Cited by the Examiner German allowed applicationto SODEC, Auslegeschrift 1,051,163, Feb. 19, 1959.

LLOYD MCCOLLUM, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTICN Patent No.3,200,319 August 10, 1965 Robert J. Tolmie It is hereb)r certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column l, line 35, for "standrd" read standard column 4, line 34, for"portions" read positions column 9, line 75, strike out "end"; column10, line 27, after "said", second occurrence, insert manual switch is inits said mid-position, said Signed and sealed this 22nd day of March1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

4. ELECTRICAL POWER AND CONTROL MECHANISM FOR AN ELECTRICAL APPLICANCECOMPRISING; A DRIVING MOTOR HAVING TWO MOTOR TERMINALS; A RECHARGEABLEBATTERY HAVING A POSITIVE AND A NEGATIVE TERMINAL; A POWER PACKCONSISTING OF TRANSFORMER MEANS HAVINGA SECONDARY AND A PRIMARY WINDING,A RESISTOR OF PREDETERMINED OHMIC VALUE CONNECTED IN SERIES WITH SAIDPRIMARY WINDING, SAID SECONDARY WINDING BEING CONNECTED AT ITS MIDPOINTTO THE JUNCTION POINT OF SAID RESISTOR AND SAID PRIMARY WINDING, ANDFULL WAVE RECTIFYING MEANS CONNECTED TO AID SECONDARY WINDING FORPROVIDING UNIDIRECTIONAL POWER AT A PREDETERMINED MAGNITUDE UNDERCONDITIONS WHERE SAID PRIMARY WINDING IS CONNECTED THROUGH SAID RESISTORTO AN ALTERNATING SOURCE OF POWER; AND ELECTRIC CIRCUIT CONNECTING MEANSSELECTIVELY OPERABLE TO A FIRST CERTAIN CONDITION CONNECTING SAIDDRIVING MOTOR ACROSS SAID BATTERY FOR ENERGIZATION THEREFROM FORROTATION IN A PREDETERMINED DIRECTION, TO A SECOND CERTAIN CONDITIONCONNECTING SAID BATTERY TO SAID POWER PACK FOR CHARGING OF SAID BATTERY,SAID ELECTRIC CIRCUIT CONNECTING MEANS ALSO BEING OPERABLE TO A THIRDCERTAIN CONDITION CONNECTING SAID DRIVING MOTOR TO SAID POWER PACK,SHORTING SAID RESISTOR IN SAID PRIMARY WINDING CIRCUIT FOR ENERGIZINGSAID DRIVING MOTOR AT A PREDETERMINED INCREASE MAGNITUDE OFUNIDIRECTIONAL POWER FOR ROTATION IN SAID PREDETEMINED DIRECTION, ANDCONNECTING SAID BATTERY FOR ELECTRICALLY ISOLATING SAID BATTERY FROMSAID MOTOR.